Synthetic resins such as polyolefins, acrylonitrile-butadiene-styrene copolymers (ABS resins), polystyrene, high impact polystyrene, polyamides, polyacetals, ethylene-propylene copolymers, etc.; natural rubbers; synthetic rubbers such as butadiene rubber, isoprene rubber, isoprene-isobutylene copolymer rubbers, styrene-butadiene copolymer rubbers, acrylonitrile-butadiene copolymer rubbers, ethylene-propylene-diene terpolymers (EPDM), etc.; petroleum products such as lubricants, fuel oils, etc.; and various other organic substances such as fats and oils, greases, etc., are susceptible to deterioration by light or oxygen. Hence, in order to inhibit such deterioration, various deterioration inhibiting agents such as, for example, phenolic compounds, e.g., 2,6-di-t-butyl-4-methylphenol, n-octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxymethyl]methane, etc., have hitherto been employed. However, any of these agents has a disadvantge that when incorporated in an organic substance at a high temperature for a prolonged period, it lacks the duration of the effect.
Under such circumstances, the present inventors have been intensively studying for the purpose of developing an excellent antioxidant which can improve such disadvantage, and have discovered that acetylene carbamide derivatives having a specific structure represented by the above general formula (I) exhibit an excellent effect, thus having accomplished the present invention.